A system and method for separation and purification of dissolved rare earth/precious metals elements/compounds

ABSTRACT

A method for purification and separation of mixed elements, comprising at least a first free flow electrophoresis separation chamber, wherein a solution of the mixed elements is passed through the first separation chamber, an electric field submitted perpendicular to the solution flow and separating mobile ions of the solution based on electrophoretic mobility. A continuous method comprises selecting a complexing ligand, and controlling the temperature and pH of the solution. Also, a system or method for separating components of a multi-component concentrate comprising directing solution to at least a first and second channel each receiving part of the solution; each channel comprising a concentration section comprising a first transverse electric field across the channel, a fractionation section comprising a second electric field in a direction opposite the first electric field thereby distributing ions of the solution across the channel, and a flow splitter at an output of the fractionation section that divides the flow of each channel into subflows concentrated in heavier elements and concentrated in lighter elements.

FIELD OF THE INVENTION

The present invention relates to a system and a method to separate andrefine rare earth/precious metals elements/compounds. More precisely,the present invention relates to a system and method for binary ormulticomponent fractional separation and purification of dissolved rareearth/precious metals elements/compounds produced in hydrometallurgicalprocesses while they are dissolved in an acidic or weakly basic medium,without any intermediate precipitation step.

BACKGROUND OF THE INVENTION

Rare earth elements (REE) occur together in nature, and any givenmineral contains several or most of them. Production of high purityindividual rare earth (RE) elements/compounds from their ores generallyrequires two stages of processing, including mineral processing andhydrometallurgy.

Mineral processing and hydrometallurgy processing of the ore before REEpurification is relatively simple and quite achievable thoughconventional methods. However, producing individual REE from mixed REscompounds is tremendously tedious. RE processing often requires dozensof steps, each resulting in minute improvement in the complex REstreams. Separating and extracting a single REE requires a great deal oftime, resources and expertise. Today, an advanced RE refinery facilitycost hundreds of millions of dollars to build.

Most REE are currently extracted in liquid phase using a combination ofslightly selective solvent extraction dissolution in organic and aqueousstrong acids, which involve a number of cycles. High purity REconcentrates are separated into individual REE using solvent-based(mainly) or ion exchange methods. Although there are several techniquesto separate RE, most of them suffer from different types of drawbacks.For instance, solvent extraction requires a great number of cycles toachieve high purity of REE. Techniques using ion-exchanger forseparation and refinery operate with low REE concentrations in solution,which leads to very large liquid volume quantity, bulky tanks,dehydrators, pumps and etc.

There is still a need in the art for a system and a method for binary ormulticomponent fractional separation and purification of dissolved rareearth/precious metals elements/compounds.

SUMMARY OF THE INVENTION

More specifically, in accordance with the present invention, there isprovided a method of purification and separation of mixed elements,using differences between electrophoresis mobility of the elements orcoordination complexes thereof in a continuous process, comprisingselecting a complexing ligand and forming a solution of the complexingligand and the mixed elements; controlling the temperature and pH of thesolution; and submitting a flow of the solution to an electric fieldsubmitted perpendicular to the solution.

There is further provided a system for purification and separation ofmixed elements, comprising at least a first free flow electrophoresisseparation chamber, wherein a solution of the mixed elements is passedthrough the first separation chamber, an electric field being submittedperpendicular to the solution flow and separating mobile ions of thesolution based on electrophoretic mobility.

There is further provided a multi-channel separation system forpurification and separation of elements in a solution, comprising atleast a first and a second channels each receiving part of the solution;each channel comprising a concentration section, a fractionationsection, and a flow splitter at an output of the fractionation section;the concentration section comprising electrodes that create a firsttransverse electric field across the channel, and the fractionationsection comprising electrodes that create a second electric field in adirection opposite the first electric field across the channel, therebydistributing ions of the solution across the channel; the flow splitterdividing the flow of each channel into a subflow concentrated in heavierelements and a subflow concentrated in lighter elements.

There is further provided a method for separating components of amulti-component concentrate, comprising a) preparing a solution of themulti-component concentrate and a reagent; b) directing the solution toat least a first and a second channel each receiving part of thesolution; each channel comprising a concentration section comprising afirst transverse electric field across the channel, a fractionationsection comprising a second electric field in a direction opposite thefirst electric field across the channel thereby distributing ions of thesolution across the channel, and a flow splitter at an output of thefractionation section that divides the flow of each channel into asubflow concentrated in heavier elements and a subflow concentrated inlighter elements; c) repeating step b) until a target separation ofisolated components is achieved; and d) recovering the isolatedcomponents.

Other objects, advantages and features of the present invention willbecome more apparent upon reading of the following non-restrictivedescription of specific embodiments thereof, given by way of exampleonly with reference to the accompanying drawings

BRIEF DESCRIPTION OF THE DRAWINGS

In the appended drawings:

FIG. 1 is a graph showing separation results of a synthetic REE mixture(La 33%, Eu 33% and Yb 33%) in a free flow electrophoresis system in asingle pass;

FIG. 2 is a graph showing separation results of a synthetic REE mixture(La 66%, Eu 17% and Yb 17%) in a free flow electrophoresis system in asingle pass;

FIG. 3 is a graph showing separation results of a synthetic REE mixture(La 17%, Eu 17% and Yb 66%) in a free flow electrophoresis system in asingle pass;

FIG. 4 is a graph showing separation results of a synthetic REE mixture(Eu 10%, Dy 40%, Tb 40% and Yb 10%) in a free flow electrophoresissystem in a single pass;

FIG. 5 is a graph showing separation results of a synthetic REE mixture(La 10%, Nd 40%, Pr 40% and Eu 10%) in a free flow electrophoresissystem in a single pass;

FIG. 6 is a graph showing separation results of a synthetic REE mixture(Nd 50%, Pr 50%) in a free flow electrophoresis system in a single pass;

FIG. 7 is a diagrammatic view of a two-step separation of a quaternaryREE mixture when the separation in some channels are not complete in asingle pass;

FIG. 8 is a graph showing separation results of a synthetic REE mixture(La 10%, Ce 40%, Pr 40% and Eu 10%) in a free flow electrophoresissystem;

FIG. 9 is a graph showing separation results of a synthetic REE mixture(Pr 50%, Ce 50%) in a free flow electrophoresis system;

FIG. 10 is a diagrammatic view of a tubular reactor which performsbinary ionic fractionation of REE according to an embodiment of anaspect of the present invention;

FIG. 11 is a diagrammatic view of a method of multicomponent REEfractional separation according to an embodiment of an aspect of thepresent invention;

FIG. 12 is a diagrammatic view of a REE refinery system and methodaccording to an embodiment of an aspect of the present invention; and

FIG. 13 is a diagrammatic view of a chamber used according to anembodiment of an aspect of the present invention.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present method and system use electrophoretic mobility variation ofREE or precious metals in an electrical field to separate them, therebyreducing the cost of separation and circumventing intrinsicenvironmental issues of solvent based methods and systems. At thepurification stage, the present method and system remove impurities andseparate REE/precious metal elements simultaneously. The present methodand system will be hereinafter described in relation to REE.

Free flow electrophoresis (FFE) is used to fractionate REE ions, using auniform electric field applied perpendicular to a solution flow andseparating the mobile ions based on electrophoretic mobility (U_(i)).

Basically, in a FFE system, the translational flow of ions in a laminarflow regime along a channel is affected by a perpendicularelectrophoretic force exerted by a static electric field on each ion.The magnitude of this force and hence the deviation of the ions formstraight trajectories along the channel, dependent upon the charge tosize ratio of each ion, which is expressed as electrophoretic mobilityU_(i).

The present method and system provide selecting a combination ofseparation parameters based on the electrophoretic mobility U_(i) forthe separation of elements/compounds.

In the case of REE, as is the case with other properties of REE, theelectrophoretic mobility U_(i) does not vary significantly from oneelement to another. Typically, REE's U_(i) values are quite close,ranging from 72.3×10⁻⁵ cm² V⁻¹ s⁻¹ to 67.0×10⁻⁵ cm² V⁻¹ s⁻¹ forLanthanum and Lutetium for example. Consequently, purification andseparation of single REE may appear inefficient in such perspective.

However, the variation between the electrophoretic mobility U_(i) of REEcan be controlled i.e. increased for example, by controlling thetemperature and selecting a complexing ligand. The present method andsystem therefore use an adequate temperature control with a propercomplexing agent to improve the electrophoretic mobility U_(i) variationsignificantly, for an effective fractionation and separation of REE.

In a first experiment, three triadic synthetic mixtures ofnon-neighboring REE La, Eu and Yb (1 gr/L total) were prepared in adilute nitric acid (2% volume) with different REE compositions. Thesemixtures were separated in a FFE system, at a temperature of about 23°C. using background electrolyte (BGE) containing 10 mM 4-methyl benzylamine and 4 mM HIBA acting as complexing ligand. The pH was adjusted to4.4 using diluted acetic acid. The FFE system was a separation chamber60 cm long, 10 cm wide with an effective separation width of 7 cm, and a0.2 mm gap width (see FIG. 13). The separation voltage was optimized to750 V during the experiment. The flow ratio between the REE mixtures,i.e. the analytes, and the BGE was set to 1 to 10. The channels (96 innumber) coming out of the FFE system were analyzed with a spectrometerto quantify the metals.

FIGS. 1, 2 and 3 show the REE concentrations at the output of each ofthe 96 channels of the FFE system. They show that a single pass of theREE mixtures through the chamber allowed perfect separation for thosenon-neighboring REE in these three triadic synthetic mixtures.

In a second experiment, several synthetic mixtures (1 gr/L) ofneighboring REE were separated in the same FFE system as describedhereinabove using similar operating conditions as reported in the firstexperiment.

FIG. 4 shows separation of a quaternary mixture of REE (Yb 10%, Dy 40%,Tb 40% and Eu 10%) in the same method and system as describedhereinabove in the first experiment. Except channel 48, which containsboth Dy and Tb, all other channels are found to contain pure or zeroREE, to the level of detection limit.

FIG. 5 presents separation of a quaternary mixture of REE (La 10%, Nd40%, Pr 40% and Eu 10%) using the system and method described in thefirst experiment. The separation of Nd and Pr was complete except forchannels 59 to 63 where they overlapped. The solution of these channelsrequires further separation consequently in a second chamber in order toobtain pure REE.

FIG. 6 depicts binary separation of Nd and Pr, i.e. a second separationstage performed on the outputs of channels 59 to 63 of FIG. 5. Suchfurther separation is needed when a single separation pass is not enoughto provide pure REE, especially between neighboring REE. The degree ofisolation and purity of each REE at the end of the single-passseparation in the FFE system is determined by the resolution ofseparation. The separation resolution is measured based upon theconcentration of REE at the outlet of a given separation chamber withrespect to the feed specification of this chamber. When the degree ofisolation or purity of REE is not sufficient in some channels of the FFEsystem after one stage of separation (i.e. for example channels 59-63 inFIG. 5), a second, consecutive, separation stage is added to the systemwith the feed thereof connected to those channels of the first previousstage still containing mixed REE. The degree of isolation and purity ofREE may thus be improved by adding one, or more, separation step(s), toachieve pure REE, as shown for example in FIG. 6.

For instance, FIG. 7 is a diagrammatic view of a two-step separation ofa quaternary REE mixture when the separation in some channels is notcomplete in a single pass. A mixture of La, Pr, Nd and Eu is fed to thefirst separation chamber (see left handside). On the outlet of the firstseparation chamber, the separation in some channels is not complete withPr and Nd still mixed (i.e. for example channels 59-63 in FIG. 5), whileEu and La and part of Pr and Nd achieve 100% purity. Thus, a consecutiveseparation chamber is required on those specific channels in order toachieve desired purities of Pr and Nd. As shown in FIG. 7 on the righthandside, a second separation chamber is thus added with the feed fromthose channels containing a mixture of Nd and Pr (i.e. for examplechannels 59-63 in FIG. 5) at the end of the first separation chamber.The second chamber on the right handside of FIG. 7 allows a completeseparation and pure REE at the outlet of the overall system (i.e. forexample in FIG. 6).

FIG. 8 is a graph showing separation results of a synthetic REE mixture(La 10%, Ce 40%, Pr 40% and Eu 10%) in the FFE system describedhereinbefore; the REE mixture corresponds to another quaternary REEmixture with Ce and Pr as the major neighbors. In this case, some Pr isstill present in channels 64 to 69 with Ce in majority. In order tofurther separate Pr from Ce in these channels, a second pass was addedsubsequently on those specific channels.

FIG. 9 is a graph showing separation results at the outcome of thissecond pass It shows that the second pass achieved purification of theCe/Pr mixture still present at the output of channels 66 to 70 of thefirst pass to a certain level and that another pass, i.e. a third pass,of separation would further improve the separation between Ce and Pr.

Based on those separation experiments which were performed in a FFEsystem, i.e. a single channel reactor, a multi-channel separation system10 is presented for binary separation of REE, as shown in FIG. 10.

In FIG. 10, the system 10 is fed with a mixture of two REE in an aqueousacidic solution. Each channel 12, 14, 16, 18, 20, 22 of the system 10has been equipped with two sets of electrodes which create transverseelectric fields across each channel.

In each channel 12, 14, 16, 18, 20, 22, a first set of electrodes 24,26, 28, 30, 32, 34, referred to as the concentration electrodes,develops a first electric field that concentrates REE ions in liquidlayers flowing close to the wall of the channel, adjacent to thenegative plate. In each channel, a second set of electrodes 36, 38, 40,42, 44, 46, referred to as the fractionation electrodes, applies asecond electric field in the opposite direction relative to the electricfield created by the first set of electrodes, thus forcing the REE ionsto migrate across the channel toward the opposite electrode andeventually fractionating them based on variations in their respectiveelectrophoretic mobility.

As the second electric field distributes REE ions across the channel,concentration profiles of the elements are not identical across andalong the channel due to the different mobilities of the REE ions. Aflow splitter 48, 50, 52, 54, 56, 58 at the end of each fractionationsection divides the flow into two parts, including an upper part and alower part which have different concentration of each element, heavierelements being more concentrated in the upper part and lighter elements,which migrate faster, being loaded in the lower part.

An electric field of 75 V/cm was selected for both fields in theexamples given herein. In practice, it is easier to use identicalintensities, but they could be different.

Thus, turning back to FIG. 10, at conjunction A, the main (input) streamis divided into two streams (A1, A2) by an in-line splitter to start abinary separation process in the first two channels 12, 14. Bothdivision streams A1, A2 go through identical fractionation steps asdescribed hereinabove, which yield four subdivision streams B1, B2, B3,B4 at the outlet of the first two channels 12, 14. These subdivisionstreams B1, B2, B3, B4 are identical two by two, i.e. B1=B3 and B2=B4,in terms of element concentrations. The identical subdivision streamsB1/B3 and B2/B4 merge together and are directed through a secondfractionation step (from B to C in FIG. 10), in channels 16 and 18respectively, as described hereinabove. Each fractionation step yields astream richer of heavier elements and a stream heavier in lighterelements. The same division and merging is performed in conjunction C,identical subdivision streams C1/C3 and C2/C4 merging together and goingthrough a third fractionation step (from C in FIG. 10). The processcontinues until desired purity of elements is obtained. The number offractionation steps depends on the concentration of the REE in solutionas well as the efficiency of separation: for example closer REE involvedin binary separation require a higher number of fractionation steps toreach desired purity, as exemplified for example in the secondExperiment described hereinabove.

For multicomponent fractionation, a number of separation units (from Ato C in FIG. 10 for example) may be used, each separation unit dividingthe components into two groups while keeping the impurities of the firstgroup close to zero in the second group. After a first separation phase,each group may be directed through a subsequent separation phase to bedivided into its constituent elements.

FIG. 11 is a diagrammatic view of a separation system for eight REE A toH. for example. In this example, it was assumed that each separationphase (phases I, II, III) is completed after two fractionation steps(Step I/Step II). In practice, the number of fractionation steps dependson the nature of the elements which are to be separated in a given step,as well as their concentrations and the desired target purity. Thenumber of final channels is equal to the number of REE in the originalmixture A-H if all the components have to be delivered individually.

The nature of the background electrolyte (BGE), the pH value and thetemperature at each separation phase are selected for the ionic REEfractionation in order to optimize the number of fractionation steps perseparation phase. Also, the number of fractionation steps and ofseparation phases, i.e. the size of the system, depend, as mentionedhereinabove, on the electric field intensity, the residence time of theions in the electric field and the REE concentrations.

For instance, a mixture of 1 gr/L REE ions is separated using a BGEcomprising 10 mM 4-methyl benzyl amine and 4 mM HIBA, which forms acomplexing agent at pH of 4.4, i.e. for example in an acetic acidsolution, at a temperature of 23° C., under an electric field of 75V/cm, in a 4 to 5 minutes residence time.

The flow ratio between the REE mixtures, i.e. the analytes, and thebackground electrolyte BGE is adjusted depending on the nature of themixtures and the other operating conditions.

The temperature is generally selected in the range between 5 and 70° C.,for example between 15 and 25° C., for a pH between 2 and 10, forexample between 3 and 6, and a flow ratio between the REE mixtures, i.e.the analytes, and the background electrolyte BGE in a range between1/100 and 1/3, for example between 1/10 and 1/3. The ligand orcomplexing agent concentration, given as molar ratio of total ligands tototal metal ions, is selected in a range between 1/1 and 10/1, forexample between 2/1 and 5/1.

The electrodes that generate the electric fields within the channels maybe conductive plates connected to a DC power supply. The electrodes maybe inserted into the walls of the channels in direct contact with theliquid flow. Alternatively, they may be positioned outside of thechannels, inducing electrostatic field into the solution flowing inside.

The electric field intensity is selected according to the concentrationand mobility differences between the REE which are to be separated ateach phase.

The separation channels or chambers can comprise semi-permeablemembranes, such as Nafion® for example, which are conductive to protons(H⁺) and hydroxyl (OH⁻) and obstruct metallic ions and their complexes,thereby to preventing metal ions to reach the electrodes in case theelectrodes are positioned in direct contact with the liquid flow.

The REE separation output is in ionic form. Then, pure REE may berecovered from the solution in any desired solid form (i.e. carbonate,hydroxide, oxide . . . ).

FIG. 12 is a diagrammatic view of a separation method and system whichintegrate a multi-component separation method and system of the presentinvention. A REE concentrate is introduced in form of RE-oxide,RE-chloride, RE-nitrate or RE-hydroxide (step 60). Reagent 61, 62 isadded to this feed and homogenized properly (step 63). A pump 64 sendsthe resulting RE solution into a multi-component separation system 65 asdescribed hereinabove. A stream of impurities and rejected REs 77 isdiverted to a purification unit 67 (step 66). Isolated REE leave theseparation reactor 65 in multiple channels as described hereinabove(step 68). In a REE precipitation unit 69, these isolated REE arerecovered in form of Re(OH)₃ or Re₂CO₃ from the liquid phase separately70, 71, 72, 73.

The depleted solutions from the REE precipitation unit 69 (step 74) andfrom the purification unit 67 (step 75) are then processed in aregeneration unit 76 to be recycled as a recycled reagent 61. Indeed,the complexing agent in FFE separation (i.e. 4-methyl benzyl amine andHIBA in acetic acid solution as described hereinabove) is the reagent inthe overall process. This reagent is regenerated and recycled afterseparation in order to keep the process sustainable and feasible.However, since the regeneration of any reagent is limited to a certainefficiency, a make-up stream of reagent 62 may be needed.

This separation method and system allow replacing most of the multiple,complex chemical transformations usually required to separate and purifyREE. They greatly reduce costs, time, and usage of a variety of chemicalreagents that could produce environmental and safety problems. Capitalcosts are greatly reduced compared to the all-chemical methods andsystems currently being used.

Although the method and system were described hereinabove for use inseparating REE from each other, they may be used in otherhydrometallurgical methods for either concentrating or rejectingelement/compound. In the latter case, they could be used to removeimpurities directly from the solution without the need for filtrationand rewashing methods that result in valuable element/compound lossesand dilution of streams containing the values sought.

Although the present invention has been described hereinabove by way ofembodiments thereof, it may be modified, without departing from thenature and teachings of the subject invention as described.

REFERENCES

-   Kasicka, V., 2009, From micro to macro: Conversion of capillary    electrophoretic separations of biomolecules and bioparticles to    preparative free-flow electrophoresis scale: Electrophoresis, v.    30, p. S40-S52.-   Santoyo, E., R. Garcia, K. A. Galicia-Alanis, S. P. Verma, A.    Aparicio, and A. Santoyo-Castelazo, 2007, Separation and    quantification of lanthanides in synthetic standards by capillary    electrophoresis: A new experimental evidence of the systematic    “odd-even” pattern observed in sensitivities and detection limits:    Journal of Chromatography A, v. 1149, p. 12-19.

1. A method of purification and separation of mixed elements, usingdifferences between electrophoresis mobility of the elements orcoordination complexes thereof in a continuous process, comprising:selecting a complexing ligand and forming a solution of the complexingligand and the mixed elements; controlling the temperature and pH of thesolution; and submitting a flow of the solution to an electric fieldsubmitted perpendicular to the solution.
 2. The method of claim 1,wherein said selecting the complexing ligand comprises selecting thecomplexing ligand with a concentration in a range between 1 μmol/L and 1mol/L.
 3. The method of claim 1, comprising controlling a flow ratiobetween the mixed elements and the complexing ligand in a range between1/100 and 1/3.
 4. The method of claim 1, comprising controlling a flowratio between the mixed elements and the complexing ligand in a rangebetween 1/10 and 1/3.
 5. The method of claim 1, comprising controllingthe concentration of complexing ligand in a range between 1/1 and 10/1.6. The method of claim 1, comprising controlling the concentration ofcomplexing ligand in a range between 2/1 and 5/1.
 7. The method of claim1, wherein the complexing ligand comprises 10 mM 4-methyl benzyl amineand 4 mM HIBA.
 8. The method of claim 1, wherein said controlling thetemperature comprises controlling the temperature in a range between 5and 70° C.
 9. The method of claim 1, wherein said controlling thetemperature comprises controlling the temperature in a range between 15and 25° C.
 10. The method of claim 1, wherein said controlling the pHcomprises controlling the pH in a range between 2 and
 10. 11. The methodof claim 1, wherein said controlling the pH comprises controlling the pHin a range between 3 and
 6. 12. The method of claim 1, wherein the mixedelements are mixed rare earth elements or mixed precious metals.
 13. Asystem for purification and separation of mixed elements, comprising atleast a first free flow electrophoresis separation chamber, wherein asolution of the mixed elements is passed through the first separationchamber, an electric field being submitted perpendicular to the solutionflow and separating mobile ions of the solution based on electrophoreticmobility.
 14. The system of claim 13, comprising at least a secondseparation chamber, said second separation chamber being in seriesand/or in parallel with the first separation chamber for fractionationand refinery of metallic ions at the output of the first separationchamber.
 15. A multi-channel separation system for purification andseparation of elements in a solution, comprising at least a first and asecond channels each receiving part of the solution; each channelcomprising a concentration section, a fractionation section, and a flowsplitter at an output of the fractionation section; said concentrationsection comprising electrodes that create a first transverse electricfield across the channel, and said fractionation section comprisingelectrodes that create a second electric field in a direction oppositethe first electric field across the channel, thereby distributing ionsof the solution across the channel; said flow splitter dividing the flowof each channel into a subflow concentrated in heavier elements and asubflow concentrated in lighter elements.
 16. The system of claim 15,further comprising a connection merging the subflows concentrated inheavier elements from the first and second channels, and a connectionmerging the subflows concentrated in lighter elements from the first andsecond channels.
 17. The system of claim 15, further comprising aconnection merging the subflows concentrated in heavier elements fromthe first and second channels, and a connection merging the subflowsconcentrated in lighter elements from the first and second channels;further comprising a third and a fourth channels, the third channelreceiving the merged subflows concentrated in lighter elements and saidfourth channel receiving the merged subflows concentrated in heavierelements; each one of the third and fourth channels comprising aconcentration section, a fractionation section, and a flow splitter atan output of the fractionation section; said concentration sectioncomprising electrodes that create a first transverse electric fieldacross the channel, and said fractionation section comprising electrodesthat create a second electric field in a direction opposite the firstelectric field across the channel, thereby distributing ions of thesolution across the channel; said flow splitter dividing the flow ofeach channel into a subflow concentrated in heavier elements and asubflow concentrated in lighter elements.
 18. The system of claim 15,wherein the first electric field concentrates metallic ions or complexesto a first wall of the respective channel along the flow direction, andthe second electric field forces the metallic ions or complexes tomigrate across the respective channel to an opposite wall of therespective channel.
 19. The system of claim 15, wherein each channelcomprises semi-permeable membranes preventing ions to reach theelectrodes.
 20. A method for separating components of a multi-componentconcentrate, comprising: a) preparing a solution of the multi-componentconcentrate and a reagent; b) directing the solution to at least a firstand a second channel each receiving part of the solution; each channelcomprising a concentration section comprising a first transverseelectric field across the channel, a fractionation section comprising asecond electric field in a direction opposite the first electric fieldacross the channel thereby distributing ions of the solution across thechannel, and a flow splitter at an output of the fractionation sectionthat divides the flow of each channel into a subflow concentrated inheavier elements and a subflow concentrated in lighter elements; c)repeating step b) until a target separation of isolated components isachieved; and d) recovering the isolated components.
 21. The method ofclaim 20, further comprising diverting a stream of impurities andrejected components to a purification unit.
 22. The method of claim 20,further comprising processing a depleted solution from the recovery ofthe isolated components to a regeneration unit to yield a recycledreagent for use in step a).
 23. The method of claim 20, furthercomprising diverting of impurities and rejected components to apurification unit, and further comprising processing at least one of: i)a depleted solution from the recovery of the isolated components and ii)a depleted solution from the purification unit to a regeneration unit toyield a recycled reagent for use in step a).